Explain the liquid junction potential in the electrochemical cells. Propose a suitable solution for this problem.
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Two loudspeakers, 1.1 mm apart, emit sound waves with the same frequency along the positive xx-axis. Victor, standing on the axis to the right of the speakers, hears no sound. As the frequency is slowly tripled, Victor hears the sound go through the sequence loud-soft-loud-soft-loud before becoming quiet again. What was the original sound frequency? Assume room temperature of 20∘C∘C. Express your answer with the appropriate units. please write the answer neatly, another post similar to this one was difficult to read resulting in my answer being wrong. |
Part A What was the original sound frequency? Assume room temperature of 20∘C∘C. Express your answer with the appropriate units. |
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PHYS/BIOL 464 Medical Imaging Instrumentation MRI HW 7A |
1.During the magnetic resonance relaxation process after a 90° pulse:
A, Longitudinal magnetization increases
B. Transverse magnetization increases
C. Proton density increases
2. T1 and T2 values depend on:
A. Voxel size.
B. Direction of magnetic field.
C. Type of tissue.
3.Tissue characteristics which can produce a relative and increased intensity (brightness) contrast in a magnetic resonance image include which of the two following factors (choose two):
A. Short T1 values.
B. Long T1 values.
C. Short T2 values.
D. Long T2 values.
4. The process of averaging is used in MRI for the purpose of:
A. Reducing acquisition time.
B. Reducing image noise.
C. Improving detail.
D. Combining T1 and T2 contrast.
5. The amount of time necessary to acquire an MR image depends on which two factors (choose two):
A. TR
B. TE
C. Field of view
D. Matrix size
6. T1 increases with magnetic field.
A. True
B. False
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In recent times the principle of the Michelson intereferometer is being used in an attempt to detect gravitational waves (LIGO experiment). A successful measurement requires an accuracy of 10-16cm. Assuming t hat the light is reflected only once in each arm and the wavelength of the laser is 632.8 nm, calculate the relative change of the intensity in the center of the image. (for simplicity assume that the intensity is zero for minimum and 1 for maximum of the interference patterns and that the alignment is such that intensity in the center of the screen is at 0.5).
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Suppose you kept your accelerating voltage and coil current constant. How would your circular beam change if we were using a proton beam instead of an electron beam? Explain your reasoning.
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Equipment used:
Thread, dense spherical mass like a marble or a bearing, perhaps
about 0.5 – 1.0 cm in diameter. Otherwise, use a
mass that is approximately spherical, e.g., a tangerine or
apple.
Method of obtaining g:
Measure the period of 4 lengths of thread from 75 cm to 1.50 cm.
Be sure to measure the length from the support
point to the center of mass of the spherical mass at the bottom end
of the thread. For each length of thread, pull
the string from the bottom mass out to about 10 degrees from the
vertical, then let the pendulum oscillate back
and forth 20 times while measuring the time with a stopwatch.
Determine the period, T, by dividing the elapsed
time by 20.
Plot the period squared versus the length of the pendulum. The
resulting curve should be a straight line with a
period involving the acceleration of gravity. Put your data for the
length of the pendulum and the period squared
into Excel. Use LINEST to find the best fit slope for the data and
the error in the slope. Calculate the acceleration of
gravity and the estimated error of the measurement for g.
Please give an excel file here.
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A block with a mass of 0.488 kg is attached to a spring of spring constant 428 N/m. It is sitting at equilibrium. You then pull the block down 5.10 cm from equilibrium and let go. What is the amplitude of the oscillation?
A block with a mass of 0.976 kg is attached to a spring of spring constant 428 N/m. It is sitting at equilibrium. You then pull the block down 5.10 cm from equilibrium and let go. What is the amplitude of the oscillation?
A block with a mass of 0.488 kg is attached to a spring of spring constant 856 N/m. It is sitting at equilibrium. You then pull the block down 5.10 cm from equilibrium and let go. What is the amplitude of the oscillation?
A block with a mass of 0.488 kg is attached to a spring of spring constant 428 N/m. It is sitting at equilibrium. You then pull the block down 10.2 cm from equilibrium and let go. What is the amplitude of the oscillation?
A block with a mass of 0.488 kg is attached to a spring of
spring constant 428 N/m. It is sitting at equilibrium. You then
pull the block down 10.2 cm from equilibrium and let go. What is
the frequency of the oscillation?
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A music fan at a swimming pool is listening to a radio on a diving platform. The radio is playing at a constant frequency tone when this person, clutching the portable radio, jumps. Describe the observed frequency or pitch for the following three observers. Explain your reasoning.
a) The person holding the radio
b) A person left behind on the platform
c) A person below the platform floating on a rubber raft
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A star with apparent visual magnitude mV = 3.5, absolute magnitude MB = 2.0 has parallax of 0.03 arcseconds. Does this star look red or blue in the sky? Estimate its spectral type.
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Consider an optical fiber that has a 200-μm core diameter and a 240-μm cladding diameter. (a) Show that the size of the active area in a bundle with two rings is 1.13 mm2. (b) Show that the ratio of the active area to the total cross sectional area of the bundle is 53 %.
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The coordinates of an object moving in the XY plane vary with time according to the equations x = −7.43 sin ωt and y = 4.00 − 7.43 cos ωt,
where ω is a constant, x and y are in meters, and t is in seconds.
(a) Determine the components of the velocity of the object at t = 0. (Use the following as necessary: ω.)
(b) Determine the components of the acceleration of the object at t = 0. (Use the following as necessary: ω.)
(c) Write expressions for the position vector, the velocity vector, and the acceleration vector of the object at any time t > 0. (Use the following as necessary: omega for ω and t.)
(d) Describe the path of the object in an XY plot.
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A piano tuner hears a beat every 1.60 s when listening to a 272.0 Hz tuning fork and a single piano string. What are the two possible frequencies (in Hz) of the string? (Give your answers to at least one decimal place.)
f = Hz (Smaller Value)
f = Hz (Larger Value)
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1. A block of mass m is sliding on a horizontal surface. The kinetic coefficient of friction between the block and the surface is µk. The drag force is linear with speed (FD = −ℓv, where ℓ is a constant). The initial velocity of the block is v0.
(e) Find x(t)
(f) Graph v(t)
(g) Graph x(t)
(h) Describe your solution in words.
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